[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Echinoderma
         Branch Tentaculata Eschscholtz, 1825
           Class Cystidea
             Order Agelacrina
               1 Genus Hedriaster
               2 Genus Hemicystites Hall, 1852